EmbedderMsg: port reply channels to GenericChannel (#39018)

This change ports all `EmbedderMsg` reply channels that don't use the
`ROUTER` to GenericChannel.
The remaining reply channels that use the router are blocked until
#38973 is merged.
This is a breaking change in the API between libservo and embedders.

Future work: A lot of the reply channels in this PR look like they
conceptually should be oneshot ipc channels. It might make sense to
provide a `OneshotGenericChannel` abstraction that encodes this.

Testing: No functional changes - covered by existing tests. None of the
channels changed here uses the Router
Part of #38912

---------

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>

components/shared/embedder/lib.rs

@@ -21,6 +21,7 @@ use std::ops::Range;
 use std::path::PathBuf;
 use std::sync::Arc;
 
+use base::generic_channel::GenericSender;
 use base::id::{PipelineId, WebViewId};
 use crossbeam_channel::Sender;
 use euclid::{Point2D, Scale, Size2D};
@@ -147,20 +148,20 @@ pub enum SimpleDialog {
     /// TODO: Include details about the document origin.
     Alert {
         message: String,
-        response_sender: IpcSender<AlertResponse>,
+        response_sender: GenericSender<AlertResponse>,
     },
     /// [`confirm()`](https://html.spec.whatwg.org/multipage/#dom-confirm).
     /// TODO: Include details about the document origin.
     Confirm {
         message: String,
-        response_sender: IpcSender<ConfirmResponse>,
+        response_sender: GenericSender<ConfirmResponse>,
     },
     /// [`prompt()`](https://html.spec.whatwg.org/multipage/#dom-prompt).
     /// TODO: Include details about the document origin.
     Prompt {
         message: String,
         default: String,
-        response_sender: IpcSender<PromptResponse>,
+        response_sender: GenericSender<PromptResponse>,
     },
 }
 
@@ -426,19 +427,22 @@ pub enum EmbedderMsg {
         WebViewId,
         ServoUrl,
         bool, /* for proxy */
-        IpcSender<Option<AuthenticationResponse>>,
+        GenericSender<Option<AuthenticationResponse>>,
     ),
     /// Show a context menu to the user
     ShowContextMenu(
         WebViewId,
-        IpcSender<ContextMenuResult>,
+        GenericSender<ContextMenuResult>,
         Option<String>,
         Vec<String>,
     ),
     /// Whether or not to allow a pipeline to load a url.
     AllowNavigationRequest(WebViewId, PipelineId, ServoUrl),
     /// Whether or not to allow script to open a new tab/browser
-    AllowOpeningWebView(WebViewId, IpcSender<Option<(WebViewId, ViewportDetails)>>),
+    AllowOpeningWebView(
+        WebViewId,
+        GenericSender<Option<(WebViewId, ViewportDetails)>>,
+    ),
     /// A webview was destroyed.
     WebViewClosed(WebViewId),
     /// A webview potentially gained focus for keyboard events, as initiated
@@ -448,7 +452,7 @@ pub enum EmbedderMsg {
     /// All webviews lost focus for keyboard events.
     WebViewBlurred,
     /// Wether or not to unload a document
-    AllowUnload(WebViewId, IpcSender<AllowOrDeny>),
+    AllowUnload(WebViewId, GenericSender<AllowOrDeny>),
     /// Sends an unconsumed key event back to the embedder.
     Keyboard(WebViewId, KeyboardEvent),
     /// Inform embedder to clear the clipboard
@@ -466,9 +470,9 @@ pub enum EmbedderMsg {
     /// A history traversal operation completed.
     HistoryTraversalComplete(WebViewId, TraversalId),
     /// Get the device independent window rectangle.
-    GetWindowRect(WebViewId, IpcSender<DeviceIndependentIntRect>),
+    GetWindowRect(WebViewId, GenericSender<DeviceIndependentIntRect>),
     /// Get the device independent screen size and available size.
-    GetScreenMetrics(WebViewId, IpcSender<ScreenMetrics>),
+    GetScreenMetrics(WebViewId, GenericSender<ScreenMetrics>),
     /// Entered or exited fullscreen.
     NotifyFullscreenStateChanged(WebViewId, bool),
     /// The [`LoadStatus`] of the Given `WebView` has changed.
@@ -476,21 +480,21 @@ pub enum EmbedderMsg {
     WebResourceRequested(
         Option<WebViewId>,
         WebResourceRequest,
-        IpcSender<WebResourceResponseMsg>,
+        GenericSender<WebResourceResponseMsg>,
     ),
     /// A pipeline panicked. First string is the reason, second one is the backtrace.
     Panic(WebViewId, String, Option<String>),
     /// Open dialog to select bluetooth device.
-    GetSelectedBluetoothDevice(WebViewId, Vec<String>, IpcSender<Option<String>>),
+    GetSelectedBluetoothDevice(WebViewId, Vec<String>, GenericSender<Option<String>>),
     /// Open file dialog to select files. Set boolean flag to true allows to select multiple files.
     SelectFiles(
         WebViewId,
         Vec<FilterPattern>,
         bool,
-        IpcSender<Option<Vec<PathBuf>>>,
+        GenericSender<Option<Vec<PathBuf>>>,
     ),
     /// Open interface to request permission specified by prompt.
-    PromptPermission(WebViewId, PermissionFeature, IpcSender<AllowOrDeny>),
+    PromptPermission(WebViewId, PermissionFeature, GenericSender<AllowOrDeny>),
     /// Request to present an IME to the user when an editable element is focused.
     /// If the input is text, the second parameter defines the pre-existing string
     /// text content and the zero-based index into the string locating the insertion point.
@@ -512,7 +516,7 @@ pub enum EmbedderMsg {
     /// Report the status of Devtools Server with a token that can be used to bypass the permission prompt.
     OnDevtoolsStarted(Result<u16, ()>, String),
     /// Ask the user to allow a devtools client to connect.
-    RequestDevtoolsConnection(IpcSender<AllowOrDeny>),
+    RequestDevtoolsConnection(GenericSender<AllowOrDeny>),
     /// Request to play a haptic effect on a connected gamepad.
     PlayGamepadHapticEffect(WebViewId, usize, GamepadHapticEffectType, IpcSender<bool>),
     /// Request to stop a haptic effect on a connected gamepad.
@@ -546,10 +550,10 @@ pub enum FormControl {
     SelectElement(
         Vec<SelectElementOptionOrOptgroup>,
         Option<usize>,
-        IpcSender<Option<usize>>,
+        GenericSender<Option<usize>>,
     ),
     /// Indicates that the user has activated a `<input type=color>` element.
-    ColorPicker(RgbColor, IpcSender<Option<RgbColor>>),
+    ColorPicker(RgbColor, GenericSender<Option<RgbColor>>),
 }
 
 /// Filter for file selection;